Noun
English Wikipedia has an article on:oleuropeinWikipedia
oleuropein (countable and uncountable, plural oleuropeins)
(organic chemistry) A complex glycoside, found in the leaves of olive and privet, that may have a beneficial effect on the immune system.
In addition to oleuropein, other phenolic compounds render freshly picked olives unpalatable and must also be removed or lowered in quantity through curing and fermentation. Source: Internet
Olives are soaked in lye (dilute NaOH, 2-4%) for 8–10 hours to hydrolyse the oleuropein. Source: Internet
Also, most liquid OLE is very low in oleuropein, the active ingredient you need. Source: Internet
The liquid forms are exponentially more expensive than the capsule ones: have you been able to locate that Herbs of Gold brand, with 100 mg oleuropein per capsule? Source: Internet